METEOROLOGIST JEFF HABY
VIL (Vertically Integrated Liquid) is a summation of reflectivity through a vertical column of the troposphere.
VIL is most accurate at the medium ranges from the radar site since the radar is able to sample most of
the vertical column of the storm. If the storm is too close to the radar then part of the storm will be
in the cone of silence and if the storm is too far from the radar then the bottom portion of the storm under
the lowest tilt angle will not be sampled.
The higher an
updraft penetrates through the troposphere then it is more likely significant
moisture has been
funneled and suspended in that vertical column. If it is not apparent on reflectivity which storms have the
strongest updrafts then the VIL can be used to determine which storms are most likely to have the
strongest updrafts. Higher VIL values occur with suspended
heavy rain and precipitation extending through
a deep vertical depth of the troposphere.